Means for feeding deicing liquids to airfoil surfaces



Oct. 2,1945. s. LE CLAIR 2,335,125

7 MEANS FEEDING DEICING LIQUIDS TO AEROFOIL SURFACES I Filed Nov. 2, 1942 mazfiim zgys eral direction.

Patented Oct. 2, 1945 MEANS FOR FEEDING DEIGING mourns 'ro AIRFOIL. SURFACES Camille olare Sprankling Le Clair, y Fe n Li rt enfl j Application'November 2, 1942,Serial-No. 464,186 j In Great Britain June 28, 1941 12' Claims. (01. 244-134) This invention relates to improvements in means for feeding de-icingliquids to airfoil-surfaces, such as wings, tailplanes, ailerons, rudders, fins and so on, whereby the liquid is fed through channels provided in or on the part for distribution on the surface thereof. I

--In known means of the kindreferred to difiiculty is experienced in obtaining a uniform distribution of liquid owing to the resistance to flow in the channels provided causing a steep pressure gradient therein and it is one object of the present invention to avoid this difficulty.

Another object is to provide de-icing feeding means for airfoil surfaces in the form of channel elements which offer little resistance to the flow of liquid and, therefore, low pressure gradient in the longitudinal direction, but great resistance and, therefore, high pressure gradient in the lat- Another object is to provide a channel element for feeding de-icing liquids to airfoil surfaces which has uniform flow characteristics throughout its length so that the-amount of liquid distributed per unit of channel length is mately uniform.

Another object is to provide a novel construction for channel elements of the kind referred to wherein one or any number of capillary liquid feeding strips may be-provided. In this specification a channel element having one capillary strip is referred to as a single channel element or single element; one having two capillary strips is referred to as a double-channel element or a double element; and one having more than two capillary strips is referred to as a multiple channel-element or a multiple elemerit. t l

. Another object is to provide a novel channel element having a simple construction and Wherein the thickness and spacing of the capillary strips define the size of the liquid or channel passage.

Another object is to provide a channel element having novel means for securing the parts thereof together. 1

Another object is to provide a novel channel element construction which permits great flexibility in the arrangement and placing of the capillary strips and the channel passages.

Another object is to provide a novel channel element of the kind referred to which has a minimum of parts and which is easy and inexpensive to construct.

Other objects and advantages will become apparent from the following description of preferred embodiments of the inventionrtaken in approxi- Fig. 2 is a sectional view of a double element,

and shows additional means for preservingthe spacingbetween the top and bottom metal strips;

Fig. 3 is a sectional view corresponding to Fig. 2, but shows an alternative method of preserving the spacing between the top and bottom metal strips;

Fig. 4 is a sectional view of a single element;

Figs. 5 and 6 are sectional views of multiple elements; and l i Fig. 7 is a sectional view of an alternative form of the invention. l

In the construction shown in Fig. 1, the double channel element comprises an upper strip I of metal and a lower strip 2 of metal, the strips being held in spaced relationship by means to be described hereinafter. Along each longitudinal marginal edge of the strip I there is provided a number of spaced projecting tongues 3, which are inte ral with the strip. Each longitudinal edge 'of the metal strip 2 is also formed with a number of spaced, projecting tongues 4 identical with the tongues 3 and integral with the strip. Although an alternative arrangement is shown in the drawing, it is preferred to arrange the tongues on one longitudinal edge of each metal strip between the tongues on the opposite longitudinal edge of the strip.

r'he channel element also comprises two felt strips 5 and 6. The top metal strip I is arranged on top of the felt strips 5 and .B and the bottom strip 2 is arranged beneath them, and the inner longitudinal edges of the felt strips are overlapped by the strips l and 2 to the required extent so as to provide a rectangular channel passage for the liquid between the strips land 2 and the inner longitudinal edges of the felt strips. building up the assembly of the strips l, 2, 5 and 6, the pointed ends of the tongues 3 and 4 are 40 forced, respectively, downwards and upwards,

through the felt strips 5 and 6 as shown along the right hand longitudinal edges of the top and bottom strips l and 2 in Fig. 1. Thereafter, as shown along the left hand longitudinal edges of the metal strips l and 2 in Fig. 1, those parts of the tongues which protrude through the felt are bent over inwardly so that they bear upon the lower and upper surfaces, respectively, of the strips 2 and I.

In Fig. 1 it will be seen that the tongues 3 are intended to be disposed substantially midway between the tongues 4. It has been found to be convenient to make the length of each tongue equal to about four times the thickness of the felt strips, and the gaps between the tongues may be from two to three times the width of the tongues at their bases.

In order to maintain the correct distance between the metal strips l and 2, the strip I may be formed with a number of longitudinallyspaced, inwardly-projecting depressions or spacers l. The bottom strip 2 may also be formed with a number of longitudinally spaced, inwardly-projecting depressions or spacers 8; The depth of the spacers I and 8 is substantially equal to the thickness of the felt strips 5 and 6. When the channel element is assembled, the spacers 8-. are disposed substantially midway between the spacers I. If so desired, the bases of the spacers I may be Welded to the innersurface of. the. bottom strip 2 and the bases of the spacers 8'may be Welded to the inner surface of the top strip I2.

An alternative means .for maintaining the metal strips I and 2 at the correct distance. apart is shown in Fig. 3. In this construction, the top metal strip I is formed. with a number of inwardly-proiecting spacers 9 and the-metal strip 2. is formedwith anxequal number'of inwardly-projecting. spacers Id. The depth of the spacers!) and It: is substantially equal tohalf. the thicknessof the felt strips- 5 and 6. When the channel. ele-= ment is assembled, the spacers 9 on the top'strip I* are substantially coaxial with the spacers. I on; the bottom strip 2 and the bases of each pair of adjacent spacers are in contact. If so desired, the contacting spacers may be welded together. Fig. 4 shows a single channel element, which comprises a metal U-shaped member comprising a top strip I and abottom strip 2: interconnected by a side-wall I I. A single felt strip is. clam-pedbetween thestrips. I and 21' by means of tongues; 3'

on the top: stripand tongues: 4- on. the? bottom strip.

Fig. 5 shows a multiple channel element comprising three channel passages formed by: three; pairs of opposite, top and bottom metal strips: I:

a and? 2, IA and 2A and IB and 2B, and. fourfel-t strips: 5, 6-, 5A and. 6A. It. will be seen: that the feltstrip 5 and one; longitudinal edge of the felt" strip 5 are clamped: between the strips L and 2 and: that: the opposite longitudinal edge of the: felt strip 6- is clamped between. the strips. IA and 2A. One longitudinal edge of the: felt strip 5A,

is clamped between the metal strips; IA. and: TA,

beingclamped; between the topand; bottom metal strips. IB and 2B; One longitudinal edge: of thefelt strip. 6A is also clamped. between. the'n'i'etal' strips; IB' and 2B;

The multiple channel-t element shown; Fig. 6- is similar to that shown-in Fig. 5,. but; as will seen,the left hand longitudinal edge. of the: left hand felt strip 5: and the right hand: edge of the right hand felt strip 5A are each. clamped be.- tween a metal member such as: shown. in Fig.4:- comprising opposite top and bottom strips: I: and: 2" interconnected by a side wall II As the. previously described construction, the. metalstrips I, I A, IBand I, and 2-, 2A, 2B- and Z are provided with clamping tongues such as ii and t.

It will be understood that the multiple chan-- nel' elements may comprise two or more charmerpassages.

The multiple channel element shown in Fig, 5 may be modified by adding a single channel element at the right hand edge of the multipleele-' ment. The construction can be visualized by as-- suming. that the right: hand edge of the right hand felt strip 6A in Fig. 5* is clamped between a metal member comprising top and bottom strips the: opposite longitudinal edge; of this; felt strip.-

I and 2 and a sidewall I I as shown, for example,

,case may be, to beyond the side Wall I I of the said metal member at the opposite edge of the multiple' element. In this case, however, the said metal: member need only have a top or a bottom strip I or 2 integral with a side wall II. A construction of this character including a continuous bottom strip I2 is illustrated in Fig. '7, to which. reference is now had. The edges of the separate;- ton strips I, IA and IB are again provided. with tongues such as 3 which, after having been forced through the felt, are passed through slotsformed the said. continuous or single metal. strip I2 and: then bent over in order toclamp the felt between thelatter and. said. strips. 'I'hefree: edge of: the top strip I- of. the said metal member at. the right hand. edge of, the multiple element is provided with tongues. 3 arranged. to. pass through. theadjacentfelt strip and through slots the.- said continuous or single metal strip I-2-. before being turned over againstthe outer surface of theilatteri The side wall II: is also provided with clamping tongues l3v which. are: assed through slots in the. last mentioned strip before being, turned over against the said outer surface.

The length: and width of the channel assembly is sufficient to cover or to: for-ma that part of the airfoilto. which the de-icing. liquid. is distributed.

.At one end ofa channel element or of an assembly of elements the channel passage; or passages are connected to a manifold or manifolds into which the de-icingliquid is pumped when required, the opposite ends of. the channel pas.- sages being closed.

Intheconstructionsdescribed above, the channel. elements have a. uniform thickness and the metal strips are provided with smooth inner surfaces which will offer a minimum resistance to the small flowof liquid which is usually required. The liquid isintendedi to: be distributed by capillary action through the felt;

preferred the channel. passages, and/or the felt strips may be of tapering form to suit the tapering form sometimes used for airfoils. Any suitable. capillary material such as. unglazedceramic, woven. asbestos. or; glass fibre orbundles of. inorganic fibresmay; of course, be. substituted for: the fell; referred to inthe: constructions above: described. It is not essential to use metal strips. provided the surfacesv of the: alternative material used: are smooth. and possess suflicient rigidity:

- If. preferred; the: strips 01: metal or alternative material. may be attached; ta the; felt. bystaples or the like.

I. claim:

1. Means for feeding de-icing liquids tothe surfaces of parts. of: aircraft such 3.5: airfoil's and the. like, including in combination, superimposed walls of material impervious to liquids; two= strips of capillary material; part of one of said capil-.- lary' strips: adjacent tor one of its. longitudinal edges-being positioned between said. superimposed liquid; impervious walls. on one edge of said walls, and part of the other of said capillary strips: adjacent: to once of its longitudinal edges being positioned between sai'di superimposed: wallson the; other edge of said walls, thefacing longitudi'naledges of" said capillary strips being spaced apartso that a passageway is formed between saidwalls and said strips and means integral withsaid liquid impervious wallsfor clamping said walls to said capillary strips".

2. The combination set forth in claim 1, in which said clamping means comprises a plurality of spaced apart tongues integral with said walls, said tongues being bent inwardly and passed through said capillary strips, and a portion of said tongues protruding from said capillary strips being turned inwardly across the wall on the pposite side.

3. Means for feeding de-icing liquids to the surfaces of parts of aircraft such as airfoils and the like, comprising a multiple channel element including in combination a plurality of spaced apart capillary strips, a pair of metallic walls connecting adjacent capillary strips, so that there is an arrangement of alternating capillary strips and metallic walls across the multiple channel element, said strips maintaining said walls in spaced relationship, said capillary strips and said walls forming a plurality of passageways therebetween, and means integral with said metallic walls and passing through said capillary strips for securing said walls and said strips together.

4. Means for feeding de-icing liquids to the surfaces of parts of aircraft such as airfoils and the like, comprising a multiple channel element including in combination, a plurality of spaced apart capillary strips, a continuous wall of liquid impervious material adapted to overlie all of said capillary strips and the spaces therebetween on one side thereof, a plurality of liquid impervious walls disposed on the side of said capillary strips.

opposite said continuous wall, said plurality of walls being equal in number to the number of spaces between said strips and bridging those spaces, and means integral with said walls for clamping said capillary strips between said continuous wall and said plurality of walls.

5. The combination set forth in claim 4, in which said continuous wall extends beyond the longitudinal edge of at least one end capillary strip, a, liquid impervious wall disposed on the side opposite said continuous wall and coextensive with the extension thereof, and an end wall comiecting said continuous wall and said secondmentioned wall to form a passageway adjoining said capillary strip.

6. Means for feeding de-icing, liquids -to the surfaces of parts of aircraft such as airfoils and the like, comprising at least one channel element including in combination a strip of capillary material, two spaced superimposed longitudinal metallic walls, one longitudinal edge of said capillary strip being positioned between said longi tudinal walls, a side wall connecting said longitudinal walls opposite said capillary strip and spaced therefrom to form a passageway therebetween, and means integral with said longitudinal walls and passing through said capillary strip for clamping said longitudinal walls to said capillary strip.

7. The combination set forth in claim 6, in which said clamping means comprises a plurality of tongues disposed along the edges of said longitudinal walls, each of said tongues being inserted through said capillary strip and having its protruding tip turn over, across and into contact with the outer surface of the metallic wall on the other side of said capillary strip. 7

8. Means for feeding de-icin-g liquids to the surfaces of parts of aircraft such as airfoils and the like, comprising at least one channel element including in combination at least two spaced walls of liquid impervious material, at least two other walls formed by spaced strips of capillary material clamped between said spaced walls, and means for maintaining said liquid impervious walls in spaced relationship, said spacing means comprising a plurality of spacer elements associated with each liquid impervious wall, said spacer elements having a depth substantially equal to the thickness of said capillary strips, the spacer elements on each of said walls projecting inwardly toward the oppositewall and each spacer element from one Wall being adjacent a spacer element from the other wall, so that spacer elementsfrom one wall are arranged alternately with the spacer elements from the opposite wall.

'9. A channel element comprising a generally U-shaped member formed by bending a metal strip so that it comprises two longitudinal walls integral with a side wall, a strip of capillary material disposed between said longitudinal walls with its inner edge spaced from said side wall, and means for clamping said capillary strip between said longitudinal walls comprising a plurality of spaced tongues along each longitudinal edge of said spaced walls, each of said tongues being inserted through said strip of capillary material and having its protruding tip turned over, across and into contact with the outer surface of the other spaced wall.

10. Means for feeding de-icing liquids to the surfaces of parts of aircraft such as airfoils and the like comprising at least one channel element including in combination a metallic channelshaped member, a strip of capillary material disposed between the longitudinal edges of the gap at one side of said channel-shaped member and having the major body portion thereof projecting exteriorly beyond said channel-shaped member, said strip being spaced from the closed side of said channel-shaped member to form a pas- 40 sageway therebetween, and means integral with said channel-shaped member and passing through said capillary strip to secure said channel-shaped member and said strip together.

11. Means for feeding de-icing liquids to the surfaces of parts of aircraft such as airfoils and the like, comprising at least one channel element, including in combination, a strip of capillary material, two spaced apart superimposed longitudinal, rigid liquid impervious walls, one longitudinal edge of said capillary strip being positioned between said longitudinal walls, a side wall connecting said longitudinal walls opposite said capillary strip and spaced from saidstrip to form a passage therebetween, and means including structure integral with at least-one of said walls and passing through said capillary strip for clamping said longitudinal walls to said strip.

12. Means for feeding de-icing liquids to the surfaces of parts of aircraft such as airfoils and the like, comprising a multi-channel element, including in combination, a plurality of spaced apart capillary strips, a continuous wall of liquid impervious metal adapted to overlie all of said capillary strips and the spaces therebetween on one side thereof, a plurality of liquid impervious metal walls disposed on the side of said capillary strips opposite said continuous wall, said plurality of walls being equal in number to the number of spaces between said capillary strips and bridging those spaces, and means integral with certain of said walls for securing said Walls and capillary strips in assembled relation.

CAMJLLE CLARE SPRANKLING LE CLAIR. 

